External user interface for head worn computing

A non-transitory computer-readable storage medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform a method comprising:

• displaying a line in a mixed reality environment, the mixed reality environment visible to a user of a wearable device via a display of the wearable device;
• tracking a motion of a finger of the user relative to the line, wherein said tracking comprises:
• receiving, via a sensor, a signal indicative of the motion of the finger of the user relative to the line;
• and
• obtaining images of the motion of the finger;
• determining, based on the signal, a first relative motion between the finger and the line;
• determining, based on the images, a second relative motion between the finger and the line;
• and
• determining an input sequence corresponding to one or more input strokes of the user, wherein:
• the input sequence is determined based on a comparison of the first relative motion and the second relative motion,
• the comparison indicates a movement of the line relative to the motion of the finger, and
• the determining the input sequence based on the comparison comprises compensating for the movement of the line relative to the motion of the finger.